import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * user:likai
 * Date:2022-12-21
 * Time:15:53
 */

public class Test {
    public int addAB(int A, int B) {
        // write code here
        if(A==0){
            return B;
        }
        if(B==0){
            return A;
        }
        int sum=0;
        int x=0;
        while(B!=0){
            sum=A^B;
            x=(A&B)<<1;
            A=sum;
            B=x;
        }
        return sum;
    }
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        // 注意 while 处理多个 case
        int a = in.nextInt();
        int b = in.nextInt();
        int sum=methon(a,b);
        System.out.println(sum);
    }
    public static int methon(int a,int b){
        if(a==0||b==0){
            return 1;
        }
        return methon(a-1,b)+methon(a,b-1);
    }
}
